Firearms for hunting and sport shooting come in a range of types, such as traditional hunting rifles with wood butt stocks and fore stocks to military type rifles. In the latter group, there is an interest in rifles that have military ruggedness and appearance but meet requirements for ownership and use, such as, for example, a limitation to semi-automatic mode rather than fully-automatic operation. Semi-automatic mode means that the trigger must be released for the next round to be fired. If the trigger is pulled but not released, one round only is fired.